Healthy, energy-efficient buildings are a key component in creating a healthy community and sustainable city. They are very easy to achieve through the use of the readily available, well proven and inexpensive Passive House standard
Christchurch City's draft Central City Plan is a laudable document, containing exciting goals of, amongst others, urban sustainability, a sustainable city and sustainable buildings. The document essentially outlines a city which is a healthy community in which to live.
It is my belief that in order for our community to be healthy, the people within it must be healthy. In order for our people to be healthy, we need healthy buildings in which to live, work, learn and play
Healthy buildings are clearly a highly desirable outcome, and the New Zealand Building Act, which creates the New Zealand Building Code (the standard by which our buildings are designed and built), has this as one of its core purposes, “...buildings have attributes that contribute appropriately to the health, physical independence, and well-being of the people who use them...”
We must then understand what the contributors are to healthy buildings. There are many, but the single overriding one is energy-efficiency. An energy-efficient building will easily and at little expense provide an environment that is warm and dry, all day, every day, and has clean air, free from mould and other toxins.
Unfortunately, the Building Code fails to deliver healthy or energy-efficient buildings; in fact, it seems likely that New Zealand has the worst energy-efficiency standards for buildings in the developed world. The underlying principles of the energy-efficiency provisions of the Building Code are flawed for several reasons. Firstly, the metric used to define energy-efficiency actually promotes the building of larger, more inefficient buildings. Secondly, they fail to define a measurable performance standard. Secondly, they fail to take into account the fundamental principles of energy-efficiency in buildings in a way that makes them effective.
So how then can we ensure that the buildings in our exciting new, sustainable Christchurch are energy-efficient and healthy? Thankfully there is a standard which has been delivering energy-efficient and healthy buildings across the world for 20 years.
The Passive House standard is a building energy performance standard. Despite its name it can be, and has been, applied to any type of building; there are currently over 30,000 certified Passive House buildings in the world.
The Passive House standard is very simple. It sets performance requirements for key areas of energy efficiency, including the energy required to maintain healthy indoor temperatures, the total energy used by a building for all purposes and the airtightness, or lack of draughts, of the building.
These performance standards have consistently resulted in buildings which are highly energy-efficient, inexpensive to run, and provide very healthy environments for the people who live, work, learn and play in them. The Passive House standard has been researched, monitored and documented to an impressive extent and the evidence is clear; it works.
One of the great things about the Passive House standard is that it is a performance standard, not a design standard. This means that there are no constraints on the ability of home or building owners, designers and Architects to create whatever type of building they desire. So long as it meets the performance criteria, it can be certified as a Passive House and enjoy the ongoing benefits of this standard.
The experience of people who live, work, learn and play in Passive House certified buildings is, not surprisingly, extremely positive. People talk freely about the low running costs, the health benefits and the comfort of being in a Passive House.
So how inexpensive are Passive Houses to run? If we consider the energy cost to maintain healthy indoor temperatures (at least 20°C) all year round in Christchurch, a Passive House will cost 90 – 95% less than if the same building were built to minimum Building Code standard. In fact, even though the capital investment for a Passive House building will be higher than its Code minimum counterpart, the inflation adjusted annual cost of capital repayments, energy and maintenance for a Passive House is likely to be lower than that of the Code minimum building.
If we consider a spectrum of building energy-efficiency standards, with the NZ Building Code standard at the bottom and the Passive House standard at the top, home and building owners, designers and Architects can choose where to aim for in terms of energy-efficiency. One of the important parts of the Passive House standard is the principles that underpin it; even if we choose to aim for lower down the spectrum than the Passive House standard, by applying the principles correctly we still end up with a building that is significantly healthier and cheaper to run than if we used only the Building Code standard.
So how can the Passive House standard be implemented in a Christchurch in a way that will have a meaningful impact?
Firstly, the Christchurch City Council can support the Passive House Institute NZ in its goals to educate the public and building industry about the Passive House standard. Secondly, the Council has many powers to ease the path for Passive Houses, for example Building Consent fee rebates and low interest loans for the small increase in capital investment. An ideal solution would be a bylaw which sets minimum, and gradually increasing, performance standards for the energy-efficiency of buildings in a way that provides actual, measurable results.
Unfortunately, the Building Act specifically prohibits Councils from enacting bylaws which improve on the dismal standard in the Building Code. So thirdly, the Council can lobby Government to allow Councils to enact bylaws which require an improvement in the energy-efficiency, and health, of the buildings and therefore the people of Christchurch.
Healthy, energy-efficient buildings are a key component in creating a healthy community and sustainable city. They are very easy to achieve through the use of the readily available, well proven and inexpensive Passive House standard.